If the JP wiki is correct and I'm interpreting it correctly, breeding two black chocobos won't necessarily yield a black because you can have black chocobos with r/b/g color genes. That said, the best way to get a black chocobo is by breeding two blacks, or doing isnm uncapped.
1. I usually go for sports plan because my male chocobo is much better than the female I breed with. Gourmet/Sports/Hiking are all fine options, Gourmet/Sports will help your chocobo in the beginning of it's life (assuming you're going physical path first).
2. Yup you just need to do the quest for it when the time is right.
Obtaining your Chocobo Whistle.
3. You do certainly. It's going to be a bit more work though. You don't even need to be born with any abilities to have a great racing chocobo, you just need patience. Of course it's far more convenient to be born with abilities and the like.
np~ :3